The present invention relates generally to blast cabinets and, more particularly, to a uniquely configured centrifuge media separator that may be included with the blast cabinet and which is specifically adapted to separate blast particulate from fine particulate such that the blast particulate may be recycled through the blast cabinet while the fine particulate may be removed from the blast cabinet in order to improve the visibility of a workpiece being blasted within the blast cabinet.
Blast cabinets are typically utilized to clean or generally prepare surfaces of a workpiece by directing high pressure fluid containing abrasive blast media or blast particulate toward the workpiece. The abrasive blast particulate is typically a relatively hard material such as sand, sodium bicarbonate (i.e., baking soda), metallic shot or glass beads although many other materials may be selected for use as the blast particulate. FIG. 1 illustrates a typical blast cabinet such as that which is commercially available from MEDIA BLAST & ABRASIVES, INC. of Brea, Calif. The blast cabinet typically includes a housing supported on legs. The housing defines a generally air tight enclosure having a pair of arm holes with gloves hermetically sealed thereto such that an operator may manipulate a blast hose and/or the workpiece for blasting thereof within the enclosure. The blast hose is configured to direct the high pressure fluid such as air carrying the blast particulate at high velocity toward the workpiece surfaces. The blast cabinet typically includes a transparent window to allow the operator to manipulate the workpiece and to visually observe the progress of the blasting.
During blasting, the blast particulate bounces off of the workpiece and is generally violently thrown about within the enclosure such that a portion of the blast particulate normally breaks down into smaller dust-like particles hereinafter referred to as fine particulate. In addition, surface coatings, dirt and scale that are abraded from the workpiece by the blast media contribute to the formation of fine particulate within the enclosure. The fine particulate is too small to be effective as a blast medium and therefore must be eventually removed from the blast cabinet. In addition, the fine particulate is of such small size such that it may be suspended in the air within the enclosure of the blast cabinet. Over time, the gradual buildup of the fine particulate can create a foggy or clouded environment within the enclosure which visually impairs or obstructs the operator's view of the workpiece. Due to health and safety regulations and environmental restrictions, the particulate-filled air cannot simply be exhausted to the atmosphere. Rather, the particulate-filled air must be filtered prior to exhaustion in order to remove the fine particulate carried therein.
Accordingly, many prior art blast cabinets are ventilated and include filters such that at least a portion of the fine particulate may be purged from the air. The filters may be configured as a replaceable cartridge filter or as a tube style filter. Regardless of its specific configuration, the filter traps the fine particulate during continuous exhaustion of the air from the enclosure. In this manner, visibility of the enclosure is enhanced such that the operator may more clearly observe the workpiece during blasting. Unfortunately, gradual buildup of the fine particulate on the filter reduces its filtering efficiency such that the filter must be periodically cleaned and/or replaced. In addition to filtering the fine particulate, the filter may also trap some of the blast particulate. The gradual buildup of the blast particulate increases the frequency of filter replacement. Furthermore, blast particulate which may otherwise be recycled is unintentionally discarded during replacement of the filter. Continuous supplementing of the blast particulate to replace the discarded blast particulate results in an increase in the operating cost of the blast cabinet.
As can be seen, there exists a need in the art for a simple blast cabinet having the capability to purge fine particulate from air prior to its exhaustion out of the enclosure in order to improve the operator's visibility of the workpiece within the enclosure. In addition, there exists a need in the art for a blast cabinet wherein blast particulate may be separated from fine particulate such that the blast particulate may be recycled through the blast cabinet. Furthermore, there exists a need in the art for a blast cabinet wherein the frequency of filter replacement is reduced such that the overall operating cost of the blast cabinet is reduced. Finally, there exists a need in the art for a blast cabinet wherein the incorporation of the centrifuge media separator eliminates the need for a filter.